The presently disclosed and/or claimed inventive concept(s) relates to a method and a device for producing a beverage from a capsule, for example by extracting at least one beverage ingredient contained in the capsule. The method and device of the presently disclosed and/or claimed inventive concept(s) apply a step of prewetting of the at least one beverage ingredient in the capsule, before the beverage ingredient is extracted and the beverage is dispensed.
Prewetting is generally known from the state of the art. For example, the state of the art proposes supplying a capsule containing a beverage ingredient with a predefined quantity of water, so that the beverage ingredient is soaked with the water. After pausing for a few seconds (by interrupting the water supply into the capsule) for prewetting, the water supply into the capsule is resumed, in order to extract a beverage from the beverage ingredient and to dispense the beverage from the capsule. Prewetting has the advantage that the extraction quality of the beverage ingredient, which may for example be roast or ground coffee, is improved. In particular, aromatic compounds of the beverage ingredient are better captured by the water before being dispensed as the beverage.
EP 0 250 810 A1 discloses a capsule, which is provided with a delivery membrane having a line of weakening that breaks, when the pressure in the capsule reaches a certain threshold value. In a prewetting phase, water is introduced into the capsule at a certain pressure value, in order to make coffee contained inside the capsule swell but to keep the delivery membrane unharmed. The water slowly distributes in the coffee bed, and the water supply is shortly stopped as long as the delivery membrane is still closed. The prewetting phase is maintained for a couple of seconds, until the coffee in the capsule is uniformly wetted and the aromatic compounds of the coffee are well captured by the water. Thereafter, air is injected into the capsule, in order to tear the delivery membrane along its line of weakness, and to dispense the extracted beverage from the capsule.
EP 2 001 343 B1 discloses a capsule, which is provided with water for prewetting at a pressure of at least 3 bar during a period of 1 s to 60 s. Thereafter, an outlet of the capsule is opened, and the extracted beverage is dispensed. The pressure required for the prewetting phase is detected by a pressure detector.
A problem with detecting the pressure as described above is that a measurement signal output from the pressure detector is not precise enough. In particular, when the pressure condition to be reached is detected by the pressure detector, the delivery membrane of the capsule is generally already perforated. Additionally, when there is too much water in the capsule, the coffee bed may be compacted and as a consequence the pressure in the capsule may increase too much, and make the further coffee extraction difficult. In the worst case, the pump supplying the water into the capsule blocks.
The state of the art further describes a method, in which the pressure is maintained by feeding a preset volume of water into an extraction chamber or a capsule by operating a water pump for a preset period of time. However, also for this method the pressure detection is not precise enough. This is particularly due to the fact that the volume of water depends on the volume of coffee contained in the capsule.
In view of the state of the art and the above mentioned problems, there is need for a method and device, which allow determining more precisely and more clearly the time point, at which the capsule is correctly filled with water for prewetting.